Effect of substrates on bioleaching of heavy metals from spent nickel metal hydride batteries

The mixed cultures of thiobacillus thiooxidans (At. t) and thiobacillus ferrooxidans (At. f) were used in bioleaching experiments of spent nickel metal hydride batteries. The influences of the different substrates were studied. The results obtained indicated that the mixed of pyrite and elemental sulfur increased the leaching rate of Ni and Co in the spent nickel metal hydride batteries. After 18 days of bioleaching, the optimal leaching rate of Ni and Co reaches to 94.8% and 86.5% respectively in the treatment of mixing of the two substrates; while the leaching rate of Ni and Co was 68.6% and 41.5% respectively in the treatment of addition of single pyrite; in the treatment of single elemental sulfur the leaching rate of Ni and Co was 92.4% and 73.1% respectively.